I have the power battery ordered for my S2 has taken all 1650mAh 3500mAh Power. If one uses the Navi, WiFi, Bluetooth and maybe Haetset etc. in ranges of smartphone battery to day. With the new battery which is no longer a problem. A previously very positive conclusion. There is only one drawback, he does not fit in the dock as it is logically a bit thicker. This is also a good alternative when something very thin and fast fragile original cover S2 is broken.